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Comparison · 2 models · Updated Oct 4, 2026

Gemini 2.5 Flash-Lite vs GPT-6 Luna

Gemini 2.5 Flash-Lite comes out ahead, 85 to 78 on our weighted score, and it is the cheaper option too.

  1. Our pick

    Google

    Gemini 2.5 Flash-Lite

    Released Jun 17, 2025

    85/100
    • ECI133.9
    • Price$0.10 / $0.40
    • Context1.05M
    Full specs Remove Gemini 2.5 Flash-Lite

  2. OpenAI

    GPT-6 Luna

    Released Sep 22, 2026

    78/100
    • ECI—
    • Price$0.10 / $0.50
    • Context1.05M
    Full specs Remove GPT-6 Luna

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Gemini 2.5 Flash-Lite is our pick

Gemini 2.5 Flash-Lite is the better all-round choice, scoring 85/100 against GPT-6 Luna (78). It leads on price and inputs & features. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.

  • CapabilityNot enough dataNo independent benchmark covers every model here yet
  • Lowest priceGemini 2.5 Flash-LiteGemini 2.5 Flash-Lite $0.175 · GPT-6 Luna $0.20 per 1M tokens (3:1 blend)
  • Longest contextAbout the sameGPT-6 Luna 1,050,000 · Gemini 2.5 Flash-Lite 1,048,576 tokens
  • Widest inputsGemini 2.5 Flash-LiteGemini 2.5 Flash-Lite: Text, Images, PDFs, Audio, Video · GPT-6 Luna: Text, Images, PDFs
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightGemini 2.5 Flash-LiteGPT-6 Luna
Price50%8683
Inputs & features30%10080
Context window20%6161
Overall100%85/10078/100

Left out because at least one model lacks the data: capability. The remaining weights were rescaled.

02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

Gemini 2.5 Flash-Lite vs GPT-6 Luna specifications side by side
SpecificationGemini 2.5 Flash-LiteGoogleGPT-6 LunaOpenAI
Capability
Capabilities Index (ECI)133.9—
ECI rank#118 of 148—
GPQA DiamondGraduate-level science questions—90.5%
FrontierMath Tiers 1–3Research-level mathematics—79.0%
OTIS Mock AIME 2024–2025Competition mathematics—98.9%
SimpleQA VerifiedShort factual questions—41.4%
Price per million tokens
Input$0.10$0.10
Output$0.40 (best)$0.50
Cached input$0.01$0.01
Blended (3:1)$0.175 (best)$0.20
Long-context rateSame rateOver 272K: $0.20 / $0.75
Price sourceOfficial Google APIOfficial OpenAI API
Limits
Context window1,048,576 tokens1,050,000 tokens (best)
Max output65,536 tokens128,000 tokens (best)
Inputs and features
TextYesYes
ImagesYesYes
PDFsYesYes
AudioYesNo
VideoYesNo
ReasoningYesYeslow · medium · high · xhigh · max
Tool callingYesYes
Structured outputYesYes
Availability
WeightsProprietaryProprietary
API model IDgemini-2.5-flash-litegpt-6-luna
API providers2024 (best)
ReleasedJun 17, 2025Sep 22, 2026
Knowledge cutoffJan 2025May 18, 2026
03 — Cost

What would a month cost?

Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.

  • Gemini 2.5 Flash-Lite$1.80
  • GPT-6 Luna$2.00
04 — Questions

Which should you choose?

Which is better: Gemini 2.5 Flash-Lite or GPT-6 Luna?

Gemini 2.5 Flash-Lite is the better all-round choice, scoring 85/100 against GPT-6 Luna (78). It leads on price and inputs & features. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.

Which is cheaper, Gemini 2.5 Flash-Lite or GPT-6 Luna?

Gemini 2.5 Flash-Lite is cheaper at $0.10 input / $0.40 output per million tokens (official Google API price). GPT-6 Luna costs $0.10 input / $0.50 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $0.175 per million tokens for Gemini 2.5 Flash-Lite versus $0.20 for GPT-6 Luna (1.1× as much).

Which scores higher on benchmarks?

There is no independent benchmark that covers both models yet. Gemini 2.5 Flash-Lite has an ECI of 133.9 and GPT-6 Luna has not been scored yet.

Which is better for coding?

There are no published SWE-bench Verified results for Gemini 2.5 Flash-Lite and GPT-6 Luna yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. Both support tool calling for agent workflows.

Which has the bigger context window?

Their context windows are effectively the same size: Gemini 2.5 Flash-Lite 1,048,576 and GPT-6 Luna 1,050,000 tokens. Maximum output per response: Gemini 2.5 Flash-Lite up to 65,536, GPT-6 Luna up to 128,000 tokens.

Which can read images, PDFs, audio or video?

Gemini 2.5 Flash-Lite accepts text, images, PDFs, audio and video; GPT-6 Luna accepts text, images and PDFs. Gemini 2.5 Flash-Lite handles the widest range of inputs.

Are any of these open source?

No. Gemini 2.5 Flash-Lite and GPT-6 Luna are proprietary and only available through APIs and apps.

Which is newer?

GPT-6 Luna is the newest, released Sep 22, 2026. Gemini 2.5 Flash-Lite came out Jun 17, 2025. Knowledge cutoff: Gemini 2.5 Flash-Lite Jan 2025, GPT-6 Luna May 18, 2026.

How do you decide the winner?

Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.

05 — Keep comparing

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